With the advance in science and technology, fingerprint recognition modules with a fingerprint recognition function have been widely set in electronic devices and have become one of the standard configurations of the electronic devices. A user may carry out identity recognition by using the fingerprint recognition module, so as to further unlock the electronic device or perform an operation on a software interface.
In the prior art, as shown in FIG. 1, FIG. 1 is a cross-sectional view of a conventional package structure of a fingerprint identification chip. In FIG. 1, a fingerprint identification module 20 is packaged by using a land grid array (LGA) technology and includes: a fingerprint identification chip 21, a substrate 22, an epoxy molding compound (EMC) layer 23 covering the fingerprint identification chip 21 and the substrate 22, a cover plate 24, a flexible print circuit (FPC) 25, and a reinforcing plate 26. An upper surface of the fingerprint identification chip 21 is provided with a bonding pad 211. The substrate 25 is provided with a metal contact 221. The bonding pad 211 is electrically connected to the metal contact 221 through a wire W.
In the prior art, the thickness of the cover plate 24 of the fingerprint identification module 20 is between 120 μm and 250 μm. The thickness of the substrate 22 is between 130 μm and 310 μm. The thickness of the fingerprint identification chip 21 is between 150 μm and 400 μm. In order to protect the wire W and maintain mechanical strength thereof, the thickness of the EMC layer 23 is usually the thickness of the fingerprint identification chip 21 plus 50 μm. The thickness of the FPC 25 and the thickness of the reinforcing plate 26 are both 120 μm. In addition, after packaging is completed, it is necessary to add the thickness of a pouring sealant, which is approximately 20 μm, and the thickness of tin soldering, which is approximately 60 μm. In the current trend of making electronic devices lighter and thinner, although the thickness of the fingerprint identification module 20 manufactured by using a conventional packaging technology can be as thin as 770 μm, the shrinkage characteristic of packaging materials may cause the fingerprint identification module 20 to warp and cause the fingerprint identification module 20 to lose the due mechanical strength.
Accordingly, how to provide a package structure of a fingerprint identification chip so that the fingerprint identification chip can avoid warping while maintaining desirable mechanical strength thereof during a thinning process is a technical issue to be solved by the present invention.